I can really only see 2 plausible theories for what happened at the end there:

1) Ai-chan made a "wish" that brought back to life the original Alis (since the alternate Alis disappeared with that alternate world after Ai-chan was pushed thru the portal). A bit unlikely though since I think that would be out of character for her to make a wish of bringing someone back to life, especially since she's a gravekeeper who buries the deceased, and not one that brings to life those that have already passed on.

2) Since u don't actually see Ai-chan physically go thru that portal thing at the end when Alis tries to push her thru it, she probably didn't actually go thru it, and Ai was then able to physically drag Alis thru the portal with her (knowing her, she probably did!). We already know that Alis can go in and out of the portal and still be alive. Furthermore, the context of Alis and Ai's conversation, too, at the end, seemed to greatly indicate that it was indeed possible for Alis to continue living in a world where his original self had already died. And when u listen to their conversation at the end, Ai questions him why he wants to disappear alone (and Alis responds that it is because he's not the original and the original is already dead and buried), and Ai responds that even if the world rejects him, she will accept him - Ai doesn't say that last part about accepting him, but instead throws herself at him and embraces him, basically saying that she will accept him, even if the world does not since he's not the original and is supposed to be dead. I'd imagine (even though we didn't really see it) Ai-chan was able to avoid going thru that portal, and then probably put her foot down and told Alis that she's not leaving without him, and that if he stays, then she's staying, too! Kinda similar to how Ai-chan acted during the Goran Academy arc when Tanya had decided to stay behind by herself. I can totally see her doing this with Alis! Plus, at the end, u don't even see Alis's grave dug up, it would probably have to be dug up if the original was brought back to life. Therefore, I believe the original Alis is still dead and buried, while the "alternate" Alis still exists! At least, that's the way I'm interpreting this ending for now!

Somehow I missed your post while browsing through this thread searching for an answer, but it explains it really well, so tyvm.

Can anyone please explain the contradiction of "15 years ago when god abandoned earth, no more children could be born" yet through out the series there are tons of children under the age of 15? I need answers

Caught the OVA on the dark side today. I was bummed when it started out at an onsen, but that's only one of three mini-episodes that all happen at various times in the story up to this point. The third was my favorite, it was gorgeous.

Can anyone please explain the contradiction of "15 years ago when god abandoned earth, no more children could be born" yet through out the series there are tons of children under the age of 15? I need answers

The only kids younger than 15 besides Ai are either dead and stopped aging, or were caught in the timeloop.

for the ending of this anime, i think that since ai really wanted/wish Alice to survive and come with her and since she is half human i think that god heard her wish and granted it so now alice is alive with his original body in the real world. i really hope they have a second season cuz i think that the author has more to write plus i heard that 1 season of the anime was 4 volumes out of 8 of the light novel. so hopefully there will be another season cuz there are so much to go for and im sure we all want to know what really happened with alice and ai and how he survived and all.